The sound of the explosion
was heard and noted some 3,000 miles away. There was a noticeable drop in average temperature
worldwide over the year or two immediately following due to the amount of dust that had been thrown into the atmosphere. Sunsets would likely have looked fantastic
for those years.
For those who are interested, I recommend the book Krakatau : The Destruction and Reassembly of an Island Ecosystem by Ian Thornton (available new from resellers such as Amazon.com). There's an older book titled Krakatau, 1883 : The Volcanic Eruption and Its Effects by Simkin & Fiske; it was published in paperback in the 1980s, and is (I believe) out of print. I skimmed a copy at my local library. Some more cool factoids from those books:
- The original island was approximately 3 miles by 5 miles. When the explosion was over, around 1/3 of that remained above the surface, and new islands of volcanic debris (lava, ash, pumice) had formed just north of it, where previously the ocean had been around 100 feet deep.
- A tsunami from the explosion was recorded as reaching Aden some 12 hours after the explosion, reaching a height of over 60 feet. Aden is 3800 nautical miles from Krakatoa.
- The dust cloud completely encircled the equator within about two weeks.
- Recording barometers showed as many as seven passages of the shock wave through the atmosphere as the wave travelled around the globe, constructively interfering with itself in places.
- Worldwide temperatures that year dropped (according to various sources) between 0.5 and 1.5 deg. Centigrade from the ash blocking sunlight.
- Three months later, the ash had reached northern latitudes and created a couple of years of really intense sunsets- so ruddy that at least three East Coast U.S. cities dispatched fire crews to deal with supposed mass fires the first night they were seen.
- 10 months after the explosion, rafts of pumice washed ashore on the other side of the Indian Ocean (Africa's east coast, the Gulf of Arabia, and India). Many of them contained miniature ecosystems, being large enough to support life - on some, actual sapling trees were found. Sightings of such debris rafts continued for two years around the eastern hemisphere.
Update: Simon Winchester has a book out called Krakatoa: the day the world exploded, August 27, 1883. I haven't read it myself yet.
Hell hath no fury like the mountain aroused.